CX3CL1 and idiopathic pulmonary fibrosis: On normal lung, CX3CL1 and CX3CR1 are found in the alveolar and bronchial epithelium, as well as in vascular endothelium, while on IPF lung there was also positive staining in the fibrotic tissue, in fibroblasts and in alveolar hyperplastic cells and glandular alterations (Figure 1A).